Suspension system using optically recorded information, vehicles including suspension systems, and methods of using suspension systems

ABSTRACT

A method for controlling a suspension system of a vehicle, as well as suspension systems, and a vehicle including a suspension system is provided. The suspension system may include at least one adjustable damping device that is controlled via a control signal, such as from a controller of the suspension system, in order to dynamically adjust the damping characteristic of the damping device. The control signal may be generated on the basis of at least one of current driving dynamics data and optically recorded information about an area of a ground surface.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to German Application No. 10 2014 206481.3, filed on Apr. 4, 2014, the contents of which is herebyincorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to suspension systems using opticallyrecorded information, as well as vehicles including such suspensionsystems and methods of using the suspension systems.

BACKGROUND

Suspension systems used in vehicles are mainly used to decouple thevehicle structure from a ground surface on which a vehicle travels, andto balance wheel loads. Damping devices, such as shock absorbers, aretypically used for this purpose. Besides conventional (passive) dampingdevices, such as shock absorbers, active damping devices may be used.Passive damping devices are a compromise between the requirements forvehicle stability, vehicle safety, and vehicle comfort. Active dampingdevices, in contrast, have the advantage that their damping behavior canbe varied during operation. Although such passive and active dampingdevices have been effective in decoupling a vehicle structure from aground surface, further improvements may be made to suspension systemsthat include such damping devices.

SUMMARY

In accordance with various exemplary embodiments, the present disclosureprovides a method of controlling a suspension system for a vehicle. Themethod comprises inputting first control information based on currentdriving dynamics data, inputting second control information, based onoptically recorded information about a ground surface area the vehiclewill travel, to a controller for the suspension system, generating acontrol signal with the controller, based on at least one of the firstcontrol information and the second control information, and controllingat least one adjustable damping device of the suspension system todynamically adjust a damping characteristic of the at least one dampingdevice.

In accordance with various exemplary embodiments, the present disclosurefurther provides a suspension system comprising a visual system, atleast one adjustable damping device having an adjustable dampingcharacteristic, and a controller. The visual system is configured torecord optical information of a ground surface area a vehicle willtravel. The controller is configured to receive first controlinformation based on current driving dynamics data detected by at leastone vehicle sensor and receive second control information based on theoptically recorded information. The controller is further configured togenerate a control signal based on at least one of the first and secondcontrol information to control the at least one adjustable dampingdevice.

Additional objects and advantages of the present disclosure will be setforth in part in the description which follows, and in part will beobvious from the description, or may be learned by practice of thepresent disclosure. Various objects and advantages of the presentdisclosure will be realized and attained by means of the elements andcombinations particularly pointed out in the appended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the present disclosure.

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the presentdisclosure and together with the description, serve to explain theprinciples of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantageous details and effects of the present disclosure areexplained in detail below using an exemplary embodiment illustrated inthe following figures. In the figures:

FIG. 1 schematically depicts a visual system of a vehicle, according toan exemplary embodiment of the present disclosure.

FIG. 2 shows an exemplary illustration of a relative height profile,determined from an image of a visual system in accordance with thepresent teachings, in relation to a ground surface to be travelled by avehicle.

FIG. 3 schematically depicts a control system for a suspension of avehicle, according to an exemplary embodiment.

FIG. 4 schematically depicts a method for using a suspension system of avehicle, according to an exemplary embodiment.

FIG. 5 schematically depicts the calculation of the second control term,according to an exemplary embodiment.

FIG. 6 schematically depicts a control system for a suspension of avehicle, according to another exemplary embodiment.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to various embodiments, examples ofwhich are illustrated in the accompanying drawings. However, thesevarious exemplary embodiments are not intended to limit the disclosure.To the contrary, the disclosure is intended to cover alternatives,modifications, and equivalents. In the drawings and the description,similar elements are provided with similar reference numerals. It is tobe noted that the features explained individually in the description canbe mutually combined in any technically expedient manner and discloseadditional embodiments of the present disclosure.

The various exemplary embodiments described herein contemplate systemsand methods of controlling a vehicle suspension system, such as avehicle suspension system including one or more damping devices.According to an exemplary embodiment, a first control term is calculatedon the basis of current vehicle driving dynamics data and a secondcontrol term is calculated on the basis of optically recordedinformation, which can be obtained by a visual system of a vehicle. Acontrol term may be, for example, a calculation based upon one or morevariables. A control term may also be referred to as control informationherein. Both the first control term and the second control term areinput to a low-level controller for a vehicle suspension system, whichgenerates a control signal for controlling the vehicle suspension systemon the basis of at least one of the first control term and the secondcontrol term.

A fully active damping device includes an actuator that simultaneouslyprovides the forces that are otherwise separately provided by a shockabsorber. For example, a fully active suspension may include an activedamping device and an active spring. A fully active suspension systemmay independently raise or lower a body of a vehicle at each wheel. Asemi-active suspension, which may also be referred to as an adaptivesuspension, may control a characteristic of an actuator, such as adamping characteristic of a damping device (e.g., independently at eachwheel), to dampen of forces applied to the suspension. In other words, asemi-active, or adaptive, suspension may adjust the firmness of anactuator, such as a damping device, to affect the quality of a ridewithout raising or lowering a vehicle body relative to the vehiclewheels. According to an exemplary embodiment, a damping device of asemi-active, or adaptive, suspension may be, for example, ahydraulically-actuated cylinder, a cylinder actuated by solenoid valvesor electromagnetically energized proportional-action valve, a cylinderincorporating a magneto-rheological fluid, or any other suitable type ofactive cylinder or shock-absorber familiar to one of ordinary skill inthe art. In one example, a cylinder includes upper and lower fluidchambers interconnected via a variable orifice, the size of which may beadjusted by controlling a motor. A semi-active, or adaptive, suspensionmay include, for example, an active damping device but not an activespring.

In comparison to semi-active, or adaptive, suspensions, fully activesuspensions, however, require high actuating energy in order to producethe necessary force in both directions, such as between the vehiclestructure and a wheel of the vehicle. Controls that facilitate stabilityof a vehicle via active damping devices are also desirable. For example,semi-active suspension devices enable the construction of a stablesuspension system, because the structural manner and operation thereofprovides force generation that is opposite to a respective direction ofmotion. The present disclosure further contemplates other suspensionsystems, such as, for example, fast active systems, active roll controlsystems, adaptive air spring systems, and fully active suspensionssystems. According to an exemplary embodiment, a fast active system isthe combination of an active damping device and a passive suspensionspring.

Therefore, the present disclosure contemplates the use of semi-activesuspension actuators (also referred to as adaptive suspensionactuators), which are generally referred to as damping devices for thevarious exemplary embodiments described herein. In view of this,suspension systems described herein may include, for example, asemi-active suspension actuator (also referred to as adaptive suspensionactuators), generally referred to as a damping device, but not an activespring. A particular damping device may be selected in view of arespective intended use and the requirements of that use.

Although suspension systems with active damping devices may be viewed asa mature and popular technology, such systems may benefit from effortsto make systems using damping devices more efficient and affordable. Forexample, a suspension system may use sensor-detected driving dynamicsdata, especially the movements of at least one wheel, as a startingbasis for control of a suspension system. A corresponding control signalbased on the sensor-detected may be calculated in real time, with whichan active damping device is ultimately controlled. However, theregulation of the suspension system effectively lags the real conditionswhen relying on sensor-detected driving dynamics data. Thus,improvements to suspension systems in which lag is minimized oreliminated (i.e., system with increased response time) would increasethe efficiency of such suspension systems.

Against this background, the present disclosure contemplates suspensionsystems that can be controlled in a manner that enables a fasterresponse to real conditions, as compared to conventional systems,whereby the stability, safety, and comfort of the vehicle can beincreased. Such suspension systems enhance the stability, safety, andcomfort during operation due to faster adaptation to real conditions.Further, the present disclosure contemplates vehicles include suchsuspension systems and methods of using the suspension systems.

The various exemplary embodiments described herein may be implementedwith a vehicle, such as, for example, a motor vehicle. The suspensionsystem may include at least one adjustable damping device. The at leastone adjustable damping device may be controlled with a control signal(e.g., a control signal generated by a controller for a suspensionsystem) in order to dynamically adjust a damping characteristic of thedamping device. The controller may be dedicated to control of only thesuspension system or the controller may be a section of a vehiclecontroller used to control various systems of a vehicle. Theconfiguration of the controller is subject to a variety ofimplementation-specific variations. For example, in some embodiments,the functions described in reference to the controller may be performedacross multiple control units or among multiple components of a singlecontroller. Further, the controller may include one or more structuralcomponents (e.g., microprocessors) that provide the function of acontroller. Any controllers or processors disclosed herein, may includeone or more non-transitory, tangible, machine-readable media, such asread-only memory (ROM), random access memory (RAM), solid state memory(e.g., flash memory), CD-ROMs, hard drives, universal serial bus (USB)drives, any other computer readable storage medium, or any combinationthereof. The storage media may store encoded instructions, such asfirmware, that may be executed by a control system or controller tooperate the logic or portions of the logic presented in the methodsdisclosed herein. For example, in certain embodiments, the controllermay include computer code disposed on a computer-readable storage mediumor a process controller that includes such a computer-readable storagemedium. The computer code may include instructions, for example, forcontrolling a suspension system according to the various exemplaryembodiments described herein.

According to an exemplary embodiment, both current driving dynamics dataand optically recorded information are input to a controller configuredto control a suspension system. The controller may be configured togenerate a control signal used to control the suspension system. Thus,the generation of the control signal may be based both on respectivecurrent driving dynamics data and also on optically recorded informationabout an area of a ground surface. However, the present disclosurecontemplates embodiments in which both current driving dynamics data andoptically recorded information are input to the controller but thecontrol signal output by the controller is based on only one of thecurrent driving dynamics data and the optically recorded information.For instance, current conditions, such as, for example, the turning ofthe vehicle (e.g., yaw rate), the operability of the vision system,height points derived from optically recorded information (e.g., heightpoints indicating an irregularity in the ground surface, such as apothole, bump, or other ground surface irregularity), or otherconditions, may cause the controller to favor one input over the over,such as by providing more weight to one of the inputs or ignoring oneinput altogether. According to an exemplary embodiment, the controllermay provide more weight to the input from the current driving dynamicsdata (e.g., the first control term), or provide no weight to the inputfrom the optically recorded information (e.g., the second control term)when a vehicle is turning at a sharp angle (e.g., has a high yaw rate)or when the visual system is obstructed or otherwise non-operational.Further, the controller may provide more weight to the input from theoptically recorded information (e.g., the second control term), orprovide no weight to the current driving dynamics data (e.g., the firstcontrol term), when height points derived from the optically recordedinformation indicate an irregularity (e.g., a pothole, bump, or otherground surface irregularity) in a ground surface the vehicle is totravel on.

The information about an area of a ground surface obtained by visualsystem may be information that contains evidence about at least an areaof a ground surface surrounding the vehicle, such as the composition ofthe area of the ground surface. According to an exemplary embodiment,the area of a ground surface surrounding the vehicle is located outsidethe contact regions of the moving vehicle (e.g., wheels) with the groundsurface. The information obtained in this way about the respective areaof a ground surface may be used to enable the preparation of thesuspension system, such as by preparing one or more damping devices ofthe suspension system. In other words, the various exemplary embodimentsdescribed herein provide the possibility of expanding upon control of asuspension system by using not only the current driving dynamics data(e.g., current driving dynamics data obtained from vehicle sensors) butalso using information that does not directly relate to the respectivedamping device. Such information may not directly relate to a currentstate of the vehicle, such as the displacement of the vehicle body, butrelates to the vehicle state or at least can relate to it in the future.The information can be, for example, optically recorded informationabout an area of a ground surface obtained from a visual system of avehicle.

By using optically recorded information about an area of a groundsurface as an input to a suspension system controller, a dampingcharacteristic of a suspension system damping device may be adapted morequickly to changing road conditions, such as when an irregularity in theground surface (e.g., pothole, bump, or other ground surfaceirregularity) is encountered. Thus, a suspension system may becontrolled in a proactive manner by using the optically recordedinformation, which facilitates faster response by a vehicle suspensionsystem to real conditions. As a result, vehicle stability, safety, andcomfort are enhanced.

Because the information about the respective area of a ground surfacethrough which the travelling vehicle passes is continually changing, theinformation can preferably be temporarily stored, such as, for example,in an electronic memory of the suspension system controller oraccessible by the controller, according to an exemplary embodiment. Theoptical information may be recorded by a visual system of a vehicle,which may be considered part of a suspension system or a separate systemin signal communication with at least the controller of the suspensionsystem.

According to an exemplary embodiment, the visual system includes atleast one camera disposed on the vehicle. The camera includes at leastone image-processing sensor, such as, for example, a charge coupleddevice (CCD), a complementary metal-oxide semiconductor (CMOS) typesensor, or unique or multilayer image sensor. The at least one cameramay be a multi-focal camera, a stereo camera or a mono camera orcombinations thereof. According to an exemplary embodiment, the visualsystem includes a LIDAR system or a LADAR system, or combinationsthereof, such as, for example, with each other and/or with a camera.These light or laser radiation emitting or capturing systems may be usedfor distance measurements between a vehicle and any relevant points ofthe ground. Further the light or laser radiation emitting or capturingsystems may be used for generating an image of an area of a groundsurface. Thus, optical information can be obtained by using a visualsystem of a vehicle that includes one or more cameras, laser systems,and/or radar systems.

All previously described systems and arrangements for obtaining opticalinformation are referred to as visual systems within the context of thepresent disclosure. According to an exemplary embodiment, a visualsystem used to record visual information is already present in avehicle. According to an exemplary embodiment, the visual system mayinclude its own internal process algorithm(s) and suitable computingcapacity, such as to provide a depth matrix at each sampling point intime. The depth matrix is an image that contains information relating tothe distance of the surfaces of observed objects from a viewpoint,according to an exemplary embodiment. The viewpoint for such an imagemay be, for example, the viewpoint of the visual system, such as theviewpoint of a camera.

In the case of a stereo camera of a visual system, the two images of theessentially mutually parallel cameras are acquired simultaneously butseparately from each other and are combined to obtain information aboutthe depth of the surroundings of the vehicle, such as in the form of adepth matrix. The depth matrix can then be used to recognize elevationsat specific regions of a ground surface in the combined images. Varioustechniques may be used to calculate the depth matrix from two or moreimages, which are familiar to one of ordinary skill in the art.

The visual system may be a system that is already present in a vehicle.By using a system already present in the vehicle, as well as sensorsalready present in the vehicle for determining current driving dynamicsdata, the various exemplary embodiments described herein can be retrofitwith little effort. In the case of vehicles that already comprise asuitable visual system and active damping device, sometimes only anadjustment in the calculation or generation of the control signal (e.g.,algorithms used by a controller of a suspension system) may benecessary. Thus, optically recorded information may then beappropriately processed, such as by the suspension system controller, inorder to be available as a further basis to generate a control signal tocontrol a vehicle suspension system in accordance with the presentteachings.

According to an exemplary embodiment, an expected displacement of astructure (e.g., a body) of the vehicle is estimated from the currentdriving dynamics data. A control term is generated on the basis of thecurrent driving dynamics data and may be referred to as a first controlterm. A first control term for a control signal used to control asuspension system, such as an adjustable damping device of a suspensionsystem, may be initially calculated on the basis of the expecteddisplacement of the vehicle structure and estimated in this manner. Ifthe optically recorded information contains no relevant informationabout any potentially necessary adjustment of the suspension system,such as an adjustment to the damping characteristic of the adjustabledamping device (e.g., no adjustment is needed on the basis of theoptically recorded information which shows area surrounding vehicle,including any potential changes in surface roughness of a road surfaceor a road surface irregularity), the first control term can be used inorder to generate a suitable control signal.

One or more sensors used to estimate suspension movements of a vehiclebody may be used to obtain driving dynamics data for calculating acontrol signal, such as on the basis of a first control term for adamping device. The calculation may take place on the basis ofdisplacement variables, such as roll, pitch, and displacement in thevertical direction of the vehicle. Besides recording the displacementvariables via corresponding sensors, a pitching rate of the vehicle canalso be calculated on the basis of the recorded driving dynamics data. Acentral measurement unit, such as an electronic memory, can be used torecord the driving dynamics data collected from one or more vehiclesensors.

According to an exemplary embodiment, an absolute height profile of anarea of a ground surface depicted in the optical recorded information isinitially calculated from the optically recorded information. The heightprofile can be used to simplify driving states that involve potentiallyrelevant height points of the recorded area of a ground surface forcontrol of a vehicle suspension system. For example, a second controlterm can be calculated on the basis of relevant height points of theabsolute height profile that differ from each other in their respectiveheight positions. A control term generated on the basis of the opticallyrecorded information may be referred to as a second control term. Thesecond control term can be used to generate a control signal for controlof a vehicle suspension system, such as upon the basis of only thesecond control term or on the basis of the second control term and thefirst control term. The controller for a suspension system may provide,for example, more weight to the input from the second control term, orprovide no weight to the current driving dynamics data (e.g., the firstcontrol term), when height points derived from the optically recordedinformation indicate an irregularity (e.g., a pothole, bump, or otherground surface irregularity) in a ground surface the vehicle is totravel on.

According to an exemplary embodiment, both control terms (i.e., thefirst control term and the second control term) are used to generate acontrol signal for controlling a vehicle suspension system, such as anadjustable damping device of the suspension system. Thus, the presentdisclosure contemplates a semi-active suspension system in which thedamping device, such as, for example, an adjustable damping device ofthe suspension system, uses both current driving dynamics data (e.g.,data based on output from one or more vehicle sensors) and opticallyrecorded information as inputs to its controller, which issues a commandsignal to control the suspension system on the basis of one or both ofthe current driving dynamics data and the optically recordedinformation.

According to an exemplary embodiment, the optically recorded informationis obtained from an area of a ground surface disposed within a detectionregion in front of the vehicle. According to an exemplary embodiment,the optically recorded information is obtained around the vehicle. Inthis manner, the optically recorded information can be used to respondto a displacement of the vehicle in every possible direction, so thatthe associated damping device of a suspension system can be controlled,even in the case of reversing the travel direction of the vehicle, byusing control signals based on the optically recorded information.Because vehicles normally travel in a straight line, at least each areaof a ground surface in front of the vehicle is recorded using a visualsystem of the vehicle.

To facilitate the determination of a height of a ground surface and/or adistance to a ground surface observed in optically recorded information,the visual system can be attached to the vehicle at a previouslydetermined height and/or horizontal distance from the center of gravityof the vehicle. The images obtained with the visual system can be used,for example, to estimate the average height profile of a ground surface,such as in a specified detection region of the visual system. A relativeheight profile for the ground surface can be generated, for example, bygrouping all recorded average height points for a ground surface withinthe detection region of the visual system. According to an exemplaryembodiment, a Reference Road Plan may be generated. The Reference Plancan be, for example, an average plan containing the maximum road pointsobserved by a visual system and/or wheel road contact points.

According to an exemplary embodiment, the distance of a detection regionfor a visual system (e.g., distance to a ground surface recorded by avisual system), relative to the vehicle, can be varied, as may bedesired. The distance to a detection region for a visual system can bevaried, for example, as vehicle speed varies. For instance, a distancein front of a vehicle at which the visual system observes and records aground surface in a detection region may be increased as vehicle speedincreases in order to provide a sufficient period of time for thecalculation of the second control term for controlling the suspensionsystem.

The height profile of the ground surface thus may cover a path for thefront wheels of a vehicle on a road surface. The respective distancebetween relevant height points and the front wheels of the vehicle,which is provided by the visual system, can be relevant to the path ofthe front wheels because the optically recorded information can be usedto determine if the calculated height profile of the ground surfaceindicates that the front wheels of the vehicle will encounter avariation in the road surface, such as, for example, a pothole. Thus,the visual system and its optically recorded information may be used toprovide an accurate estimation of when a respective height point isreached.

Because the visual system, and thus its optically recorded information,is subjected to the movements of the vehicle body while travelling, theoptically recorded information sometimes may not be suitable for directuse, such as to provide a realistic estimation of the true nature of theground surface to be travelled by a vehicle. According to an exemplaryembodiment, an absolute height profile used for the calculation of thesecond control term can be based on a previously calculated relativeheight profile, such as a relative height profile calculated during aprevious control loop or iteration. According to another exemplaryembodiment, an absolute height profile may be determined by processingoptically recorded information obtained by a visual system of a vehicle.For instance, a relative height profile may be determined on the basisof height profiles determined from the optically recorded information,which may be affected by the movements of a vehicle body. To addressthis, the relative height profile may be reprocessed to obtain anabsolute height profile. The reprocessing may compensate for movementsof the vehicle structure and/or of the vehicle, such as, for example,pitching, rolling, and/or vertical movements. According to an exemplaryembodiment, only the absolute height profile, such as the absoluteheight profile obtained via the reprocessing discussed above, is used asthe basis to calculate the second control term because only the absoluteheight profile contains an adjusted model of the real ground surface inwhich height point can be properly identified.

According to an exemplary embodiment, the time to reach a relevantheight point of a ground surface with a wheel of the vehicle associatedwith the damping device is calculated depending on the direction oftravel and/or the speed of the vehicle. In other words, the time atwhich the associated wheel just reaches the height point is calculatedon the basis of the speed and/or the direction of travel of the vehiclein relation to the recorded height points. The second control term maybe used by the controller of the vehicle suspension system to generate acontrol signal for the suspension system upon reaching the height point,such as to adjust a damping characteristic of a damping device of thesuspension system according to the current ground conditions at thattime (e.g., the ground conditions indicated by the optically recordedinformation) and/or the current driving dynamics.

In the case of further travel, height points between the detectionregion and the wheel associated with the damping device that are outsideof the detection region, and are thus lacking, may be reconstructed viaa suitable calculation. In this manner, the previously recorded heightpoints are available at any point in time, including up to at leastrespective height points so they may be appropriately taken into accountduring the generation of a control signal for a vehicle suspensionsystem. This part of the system facilitates building a map of a roadelevation while the vehicle is moving forward or backward.

According to an exemplary embodiment, the inputs for the rollingmovements of at least one wheel on the ground may be used to generate anappropriate control signal on the basis of the first control term.Therefore, the suspension system may be controlled without use of thesecond control term, such as in the absence of information about thefuture ground to be travelled (e.g., in the absence of opticallyrecorded information obtained via a visual system). For example, whenthe visual system is not functional (e.g., visibility is poor, anoptical sensor is blocked, or other technical difficulty) or when thevisual system is otherwise unable to observe the path upon which thevehicle is traveling (e.g., when the vehicle is making a sharp turn andthe visual system is oriented for a generally straight path in front ofthe vehicle), a controller for a vehicle suspension may generate acontrol signal to control the suspension system based upon the currentdriving dynamics data (e.g., the first control term) and provide lessweight or no weight to the optically recorded information (e.g., thesecond control term). However, by using both the first control term andthe second control term, based on previously optically recordedinformation, to control a vehicle suspension, the influence of groundroughness on the vehicle body and the influence of wheel movements canbe further minimized.

By using the various exemplary embodiments described herein, control ofa regulated suspension system, such as a suspension system including anactive damping device, is facilitated, whereby the stability, safety,and comfort of the vehicle can be enhanced. For instance, the visualsystem may be used to provide a preview of a ground surface to enable afaster response by the vehicle suspension to real conditions of theground on which the vehicle travels. In this way, the controller of thevehicle suspension not only responds to the current recorded respectivedriving dynamics data, but is supplied with previously opticallyrecorded information at a correct point in time, so that the opticallyrecorded information can also be taken into account when generating acontrol signal for the suspension system.

The present disclosure also relates to a suspension system for a vehiclethat is combined with a visual system as previously described. Thesuspension system of the vehicle may be configured and used according tothe various exemplary embodiments described herein. In the variousexemplary embodiments described herein, a suspension system may be anyof the following systems: an active damping system, a regulatedpneumatic suspension system, an active roll compensation system, anactive chassis system (e.g., a system that can generate activesuspension forces), or other suspension systems familiar to one havingordinary skill in the art.

According to an exemplary embodiment, a suspension system comprises atleast one adjustable damping device. The damping device may be, forexample, a shock absorber, a vehicle spring, at least one device thatacts like a shock absorber and/or a vehicle spring, or other dampingdevice familiar to one having ordinary skill in the art. The dampingdevice may be controllable by a control signal (e.g., a control signalissued by a controller of a vehicle suspension system), such that adamping characteristic of the damping device can be dynamicallyadjusted. The control signal can be generated on the basis of currentdriving dynamics data, which may be detected by one or more vehiclesensors, and/or on the basis of optically recorded information about anarea of a ground surface obtained by a visual system of a vehicle.According to an exemplary embodiment, a visual system used with asuspension system comprises, for example, a camera and/or a LIDAR deviceor other optical system used for optical recognition of an object thatis familiar to those having ordinary skill in the art. Light or laserradiation emitting systems are also known as LADAR arrangements.

Turning to the drawings, FIG. 1 depicts a side view of an exemplaryembodiment of a visual system 1 of a vehicle 3. The visual system 1 canbe located, for example, in the front region of the vehicle 3, such asin the windshield region or on a hood 2 of the vehicle 3. The visualsystem 1 may be, for example, a camera system. The visual system 1contains at least one sensor 4 (e.g., a camera sensor) to opticallyrecord the environment in front of the vehicle 3. According to anexemplary embodiment, the visual system 1 may comprise a sensor 4, suchas a camera, so that information about the depth of the environment infront of the vehicle 3 can be recorded. Other numbers of sensors 4 maybe used, such as when two sensors 4 (e.g., two cameras) are used for astereo system. The depth matrix that can be generated in this way may beused, for example, to detect unevenness of a ground surface, such aselevations and depressions in specific regions of a region of roaddisposed in front of the vehicle 3. As an alternative or in addition,the visual system 1 can be a LIDAR (which may stand for “light detectionand ranging”) arrangement or a LADAR arrangement that includes sensor 4.The visual system 1 may be configured such that only a ground surface 5located within a detection region 7 of the visual system 1 is observedand optically recorded by the visual system 1. According to an exemplaryembodiment, a portion of ground surface 5 within detection region 7 is,for example, about 0.15 m in width at a range of, for example, about 4 mto about 15 m in front of a vehicle.

The visual system 1 is connected to a controller (not shown) configuredto control the suspension system (not shown) of the vehicle 3. Theconnection between the visual system 1 and the controller can be, forexample, a physical connection, such as a wired connection, or theconnection can be a wireless connection. In the orientation depicted inFIG. 1, the visual system 1 faces forward in a direction of travel x ofthe vehicle 3.

The visual system 1 is provided in order to carry out range or depthmeasurements between at least one sensor 4 of the visual system 1 and anarea of a ground surface 5 of the ground 6 in front of the vehicle 3.For this purpose a detection region 7 of the visual system 1 (e.g., ofthe sensor 4) is directed towards an area of a ground surface 5 in frontof the vehicle 3. The detection region 7 contains a depth in thedirection of travel x and a breadth in a lateral direction y of thevehicle 3. The ground 6 may be, for example, a highway or a road, or maybe rough terrain, such as when vehicle 3 is operated off-road.

The visual system 1 may be located at a fixed height z1 relative to theground 6, such as along a vertical direction z, and at a distance x1from a center of gravity 8 of the vehicle 3, so that visual system 1 canrecord images of the environment in front of the vehicle 3. Continuousor parallel images of the visual system 1 obtained in this way may beused to estimate the average height of the ground 6 within therespective area of a ground surface 5. By grouping all the averagepoints of the area of a ground surface 5, vectors between them may becombined to construct a common relative height profile, according to anexemplary embodiment.

In the case of a forward moving vehicle 3, the height profile A of theground surface 5, which may continuously vary, that is generated coversthe respective precalculated path of the front wheels 9 of the vehicle3. A distance x2 of the detection region 7, or of the relevant points ofthe area of a ground surface 5 detected therein, relative to the frontwheels 9 of the vehicle 3 may be used to estimate when the groundsurface 5 or the respective points in the detection region 7 arereached, such as by the front wheels 9.

FIG. 1 demonstrates that a generated height profile A is substantiallyadjusted to the real profile of the schematically illustrated ground 6.Whereas a height point H1 is still within the detection region 7 of thevisual system 1, other relevant height points H2, H3 are outside of thedetection region 7 and have already been reached by the moving vehicle 3(e.g., by front wheels 9 and rear wheels 10). Height point H2 may be ahump in the ground 6, which is now in contact with at least one frontwheel 9. The vehicle suspension system, such as a damping device (notshown) associated with one or both of the front wheels 9 of the vehicle3 may be controlled, such as via control of the damping characteristicof the damping device, based on information about the area of a groundsurface 5 to be travelled that was previously optically recorded by thevisual system 1. For example, damping devices associated with each ofthe front wheels 9 may be pre-adjusted (e.g., via the controller for thesuspension system) on the basis of optically recorded informationobtained by the visual system 1 for when front wheels 9 encounter heightpoint H2 (e.g., a hump in the ground 6). As a result, the suspensionsystem provides a faster response to real conditions, and the stability,safety, and ride comfort of the vehicle are enhanced. Furthermore, aheight point H3 may be, for example, a depression in the ground 6 thatis encountered by at least one rear wheel 10 of the vehicle 3. Dampingdevices associated with the rear wheels may be controlled in a similarmanner to damping devices of the front wheels, such as to pre-adjust thevehicle suspension for the rear wheels. Thus, the vehicle suspension maybe controlled to provide a desired rolling behavior.

FIG. 2 depicts a measure for obtaining realistic information about therespective area of a ground surface 5, according to an exemplaryembodiment. Because the visual system 1 may be fixed onto the vehicle 3,the visual system is subjected to corresponding positional disturbancesdue to motion of the vehicle body the visual system 1 is connected to.For instance, at least the structure of the travelling vehicle 3 issubject to some movements, such as movements resulting from travellingover the ground 6. Even if the visual system 1 contains mechanicalcompensation (e.g., mechanical vibration damping devices) for theseinevitable positional disturbances, the present disclosure contemplatesa synchronous displacement of the visual system 1 together with thestructure of the vehicle 3.

In view of the possible disturbances to the visual system, opticalinformation obtained about the ground 6 by the visual system 1 may bereprocessed, according to an exemplary embodiment. For example, theheight profile initially obtained via the visual system 1 is a relativeheight profile A1, as depicted in the upper region of FIG. 2. As shownin the upper region of FIG. 2, the height profile has a dynamic profilein the vertical direction z, because the height profile has beeninfluenced by the respective movements of the vehicle 3. The relativeheight profile A1 may be reprocessed to compensate for the movements ofthe visual system 1. Reprocessing may support the extraction of theabsolute height profile A, which is depicted in the lower region of FIG.2, which in turn may be used to control a vehicle suspension system. Inorder to achieve this, a suitable reprocessing algorithm is thereforeused for compensation of the movements of the visual system 1.

The absolute height profile A, which is depicted in the lower region ofFIG. 2, may be based on the real profile of the recorded area of aground surface 5 in front of the vehicle 3. Thus, the vehicle (e.g.,vehicle 3 of FIG. 1) may be travelling over a bump (corresponding toarea 11 in the lower region of FIG. 2) on a flat area of a groundsurface 5 in the direction of travel x. As mentioned above, the upperregion of FIG. 2 shows the recorded profile of the relative heightprofile A1. Because of the movements (e.g., pitch, roll, verticalmovements) of the vehicle 3 or its structure, the actual bump 11 may bedetected with difficulty, as shown by the corresponding area 11 in theupper region of FIG. 2. By reprocessing the data of the relative heightprofile A1 into the absolute height profile A, the bump 11 be properlyidentified and the vehicle suspension system can be controlledappropriately.

As already explained, the preliminary evaluation of the true conditionof the ground to be travelled 6 takes place for a distance x2 in frontof the vehicle 3, wherein the distance x2 can be fixed or variable.While travelling, a displacement speed vector (longitudinal speed in thedirection of travel x and lateral speed in the lateral direction y) ofthe vehicle 3 may change constantly, such as due to how a person issteering the vehicle 3. Thus, the time to reach the respective heightpoint H1-H3 also varies. In view of this, the speed of the vehicle 3 andthe optically recorded information about the area of a ground surface 5may be monitored such that the respectively missing height pointsbetween the detection region 7 of the visual system 1 and the respectiveassociated front and/or rear wheel 9, 10 of the vehicle 3 may bereconstructed via calculation.

Independently of the information about the area of a ground surface 5optically recorded by the visual system 1, the four inputs of the ground6 on the front and/or rear wheels 9, 10 of the vehicle 3 MAY also beused to calculate the respective control signal for the associateddamping device. According to an exemplary embodiment, the inputs arecurrent driving dynamics data detected by one or more sensors. Thesensors may be, for example, displacement and/or acceleration sensorsdisposed in or on the damping device associated with a wheel of thevehicle 3. The driving dynamics data may include other types of drivingdata, such as, for example, the lateral acceleration of the vehicle 3and/or other types of vehicle driving dynamics data. The aim of usingthe data is to minimize and/or reduce the effect of any roughness of theground 6 on the structure of the vehicle 3 and the suspension movementsof the front and/or rear wheels 9, 10.

FIG. 3 depicts a process to control a vehicle suspension system,according to an exemplary embodiment. Movements of the travellingvehicle 3, especially the displacement speed v of its structure, areinitially estimated as driving dynamics data v. A first control termK_(FB) is calculated using the driving dynamics data v, which is inputto the calculation function F2 i of a controller that generates acontrol signal i used to control a vehicle suspension system G, such asone or more respective damping device of the vehicle 3. According to anexemplary embodiment, output from one or more accelerometers and/orgyroscopes may be used as driving dynamics data v to calculate the firstcontrol term K_(FB). Feedback from the suspension system G (e.g.,feedback from one or more sensors measuring suspension deflection, suchas sensors measuring damping device deflection) in the form of at leastone damping speed vector v_(s) may also be input to the calculationfunction F2 i of the controller, so that a control loop for the controlsignal i is established.

According to an exemplary embodiment, a second control term K_(FF) iscalculated on the basis of optically recorded information (e.g., an areaof a ground surface 5 in FIG. 1) obtained by a visual system of thevehicle, which is input to the calculation function F2 i of thecontroller for generating the control signal i. For example, a heightvalue r, such as the absolute height profile A discussed above, may beused as to generate the second control term K_(FF) as an input to thecalculation function F2 i for generating a control signal i forcontrolling the vehicle suspension system G, in addition to the firstcontrol term K_(FB).

According to an exemplary embodiment, the first control term K_(FB) andthe second control term K_(FF) may be used as inputs to the calculationfunction F2 i to minimize a rough ride due to respective corneringspeeds of the vehicle structure and the movements of the front and/orrear wheels 9, 10, as well as due to the contact of front and/or rearwheels 9, 10 with a ground surface under the following input conditions:

C(i)v _(s) =K _(FB)(v)+K _(FF)(r)

Here, r may represent respective height points H1-H3 of the absoluteheight profile A in FIGS. 1 and 2. The height points H1-H3 may haveheight values that deviate from one another, as indicated in FIG. 1. Thetime to reach respective height points H1-H3 may be used to control thevehicle suspension system G, such as to pre-adjust the suspension systemG and/or control the suspension system G when vehicle wheels 9, 10 reachthe respective height points H1-H3 observed by the visual system 1.According to an exemplary embodiment, the suspension system G may beconfigured to adjust the vehicle suspension, such as the dampingcharacteristic of one or more damping devices, when the height point ris input to the suspension system G. In order to control the suspensionsystem G at the time the vehicle wheels 9, 10 reach the respectiveheight points, the suspension controller may include a time varyingdelay, such as a function W, to control when the height point r is inputas a control to the suspension system G. The function W may be adjustedto vary the time at which the height point r is input as a control tothe suspension system G, such as by varying the function W as vehiclespeed varies. The function W may be, for example, a Laplace transform,used to delay to the input of a height point r to the suspension systemG. For example, the function W may have the form of e^(−T(u)s), with Trepresenting a time delay and u representing vehicle speed.

FIG. 4 depicts a method for the operation of the suspension system G,according to an exemplary embodiment. In step 100, images are acquiredby the visual system 1 and used in step 110 to calculate the relativeheight profile A1 of the area of a ground surface 5, such as a specifiedpath of vehicle front wheels 9. In step 120, an absolute height profileA is calculated by reprocessing the relative height profile A1. Step 120may be combined with step 110, such as, for example, depending on thevisual system and the processing algorithm used. The first control termK_(FB) and second control term K_(FF) are calculated in steps 130, 140,such as by calculating the first control term K_(FB) on the basis ofcurrent driving dynamics data v obtained from one or more vehiclesensors and the second control term K_(FF) on the basis of the opticallyrecorded information obtained by the visual system 1. An appropriateforce-control demand signal 12 (e.g., control signal, such as controlsignal i in FIG. 4) is determined in step 150 and input to the vehiclesuspension G in step 160, such as to one or more adjustable dampingdevices of the suspension system G. According to an exemplaryembodiment, information about the respective area of a ground surface 5to be travelled by a vehicle, which has been previously obtained fromimages of the visual system 1, is input to the suspension system G bymeans of driving dynamics data v.

FIG. 5 depicts an exemplary method for calculating the second controlterm K_(FF) for the method of FIG. 4. For this purpose, any road heightvector points 14 of the individual wheels 9, 10 on the respective ground6 currently being travelled are initially detected. The road heightvector points for each wheel 14 are used as input variables for thecalculation of a preliminary evaluation model 15 regarding expected roadcharacteristics and a damping force preliminary evaluation 16. Thepreliminary evaluation model 15 contains an event-based detection 17 anda corresponding continuous suspension model 18. Any detected eventsand/or structural speeds 19 of the vehicle, based on the preliminaryevaluation-model 15, are input to the damping force preliminaryevaluation 16. The damping force preliminary evaluation 16 includes anevent-based, shifted damping force query 20, a continuous damping forcequery 21, and an evaluator 22 for the damping force preliminaryevaluation 16.

Based on the preliminary evaluation model 15, vehicle suspension rates23 are calculated for one or more vehicle wheels 9, 10, while thedamping force preliminary evaluation 16 independently outputspreliminary evaluation damping forces 24 for the one or more vehiclewheels 9, 10. According to an exemplary embodiment, both the independentpreliminary evaluation damping forces 24 and the suspension rates 23 areinput to a preliminary evaluation quadrant check 25, which outputs acontrol value 26, such as for the damping characteristic of a dampingdevice, from which the second control term K_(FF) can be based.

Depending on the respective application, the various exemplaryembodiments described herein provide enhanced control of a vehiclesuspension system, such as a suspension system with an active dampingdevice 13, in comparison with conventional suspension control means.According to an exemplary embodiment, the damping device may use anappropriately higher or lower forces and bandwidth to provide additionalenhancement of the suspension control.

The present disclosure contemplates other configurations for acontroller of a vehicle suspension system. FIG. 6 schematically depictsa control system for a suspension of a vehicle, according to anotherexemplary embodiment. Signals from one or more vehicle sensors, such asheight sensors 200, are input to a VDM input signal layer 240, which maybe a function of a continuous control damper (CCD) control system. Datafrom a vehicle controller area network (CAN) 210 and/or data from acamera ECU 220 may be input to the VDM input signal layer 240, asindicated in FIG. 6. A road profile message and vehicle data is outputfrom the VDM input signal layer 240 to a suspension road preview (SRP)function 250, which outputs a road profile message and vehicle data to aroad profile height estimation function 260. Road profile heightestimation function 260 may include an event based detection subfunction262 and a preview to wheel road profile calculation subfunction 264. Aroad profile and event flag is output from the profile height estimationfunction 260, such as, for example, a road profile and event flag foreach vehicle wheel, and input to a preview force request function 270.The preview force request function 270 may include an event based feedforward force request subfunction 272 and a continuous force requestsubfunction 274. The preview force request function 270 outputs anunconstrained preview force to a preview quadrant control andquantization function 280. An unconstrained preview force may beprovided, for example, for each vehicle wheel. Preview forces, such asfor each vehicle wheel, are output from the quadrant control andquantization function 280 to a CCD arbitration function 290. The CCDarbitration function 290 may also receive a CCD force request 230 asinput, as indicated in FIG. 6. The CCD arbitration function 290 outputsa damper force request, such as a damper force request for one or moredamping devices of a suspension system that are schematicallyrepresented by CCD dampers 292 in FIG. 6.

Further modifications and alternative embodiments will be apparent tothose of ordinary skill in the art in view of the disclosure herein. Forexample, the systems and the methods may include additional componentsor steps that were omitted from the diagrams and description for clarityof operation. It should be noted that the features set out individuallyin the present disclosure can be combined with each other in anytechnically advantageous manner and provide other embodiments.Accordingly, this description is to be construed as illustrative onlyand is for the purpose of teaching those skilled in the art the generalmanner of carrying out the present teachings. It is to be understoodthat the various embodiments shown and described herein are to be takenas exemplary. Elements and materials, and arrangements of those elementsand materials, may be substituted for those illustrated and describedherein, parts and processes may be reversed, and certain features of thepresent teachings may be utilized independently, all as would beapparent to one skilled in the art after having the benefit of thedescription herein. Changes may be made in the elements described hereinwithout departing from the spirit and scope of the present teachings andfollowing claims.

This description and the accompanying drawing that illustrates exemplaryembodiments of the present teachings should not be taken as limiting.Various mechanical, compositional, structural, electrical, andoperational changes may be made without departing from the scope of thisdescription and the claims, including equivalents. In some instances,well-known structures and techniques have not been shown or described indetail so as not to obscure the disclosure. Like numbers in two or morefigures represent the same or similar elements. Furthermore, elementsand their associated features that are described in detail withreference to one embodiment may, whenever practical, be included inother embodiments in which they are not specifically shown or described.For example, if an element is described in detail with reference to oneembodiment and is not described with reference to a second embodiment,the element may nevertheless be claimed as included in the secondembodiment.

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities, percentages orproportions, and other numerical values used in the specification andclaims, are to be understood as being modified in all instances by theterm “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the written description and claims areapproximations that may vary depending upon the desired propertiessought to be obtained by the present disclosure. At the very least, andnot as an attempt to limit the application of the doctrine ofequivalents to the scope of the claims, each numerical parameter shouldat least be construed in light of the number of reported significantdigits and by applying ordinary rounding techniques.

It is noted that, as used in this specification and the appended claims,the singular forms “a,” “an,” and “the,” include plural referents unlessexpressly and unequivocally limited to one referent. Thus, for example,reference to “a sensor” includes two or more different sensors. As usedherein, the term “include” and its grammatical variants are intended tobe non-limiting, such that recitation of items in a list is not to theexclusion of other like items that can be substituted or added to thelisted items.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the system and method of thepresent disclosure without departing from the scope its disclosure. Itis to be understood that the particular examples and embodiments setforth herein are non-limiting, and modifications to structure,dimensions, materials, and methodologies may be made without departingfrom the scope of the present teachings. Other embodiments of thedisclosure will be apparent to those skilled in the art fromconsideration of the specification and practice of the disclosuredisclosed herein. It is intended that the specification and embodimentdescribed herein be considered as exemplary only.

1. A method of controlling a suspension system for a vehicle,comprising: inputting first control information based on current drivingdynamics data; inputting second control information, based on opticallyrecorded information about a ground surface area the vehicle willtravel, to a controller for the suspension system; generating a controlsignal with the controller, based on at least one of the first controlinformation and the second control information; and controlling at leastone adjustable damping device of the suspension system to dynamicallyadjust a damping characteristic of the at least one damping device,wherein the suspension system is an adaptive suspension system or anactive roll control suspension system.
 2. The method as claimed in claim1, further comprising: estimating an expected displacement of astructure of the vehicle from the current driving dynamics data, andcalculating the first control information on a basis of the estimateddisplacement of the structure.
 3. The method as claimed in claim 2,further comprising: calculating an absolute height profile of the groundsurface area from the optically recorded information; and calculatingthe second control information using height points of the absoluteheight profile, wherein the height points have height values thatdeviate from one another.
 4. The method as claimed in claim 3, whereinthe absolute height profile is based on a previously calculated relativeheight profile, wherein the previously calculated relative heightprofile is reprocessed to obtain the absolute height profile tocompensate for inherent movements of at least one of a structure of thevehicle and of movements of the vehicle.
 5. The method as claimed inclaim 3, further comprising calculating a time at which a wheel of thevehicle associated with the at least one damping device reaches arelative height point, wherein the calculated time depends on at leastone of a direction of travel of the vehicle and a speed of the vehicle,wherein the second control information, at the time at which the wheelreaches the relative height point, is used to generate the controlsignal to control the at least one damping device.
 6. The method asclaimed in claim 4, further comprising: obtaining the optically recordedinformation for the ground surface area at a detection region disposedin front of the vehicle; and determining a relative distance between thedetection region and the vehicle.
 7. The method as claimed in claim 1,further comprising reconstructing missing height points in the opticallyrecorded information between a detection region disposed in front of thevehicle for the optically recorded information and a wheel associatedwith the at least one damping device.
 8. The method as claimed in claim1, further comprising obtaining the optically recorded information witha visual system of the vehicle.
 9. A suspension system, comprising: avisual system configured to record optical information of a groundsurface area a vehicle will travel; at least one adjustable dampingdevice having an adjustable damping characteristic, wherein thesuspension system is an adaptive suspension system or an active rollcontrol suspension system; and a controller configured to: receive firstcontrol information based on current driving dynamics data detected byat least one vehicle sensor and receive second control information basedon the optically recorded information; and generate a control signalbased on at least one of the first and second control information tocontrol the at least one adjustable damping device.
 10. The suspensionsystem as claimed in claim 9, wherein the visual system comprises atleast one of a camera device and a LI DAR device.
 11. The suspensionsystem as claimed in claim 9, wherein the controller is furtherconfigured to generate the control signal based upon at least one of thefirst control information and the second control information.
 12. Thesuspension system as claimed in claim 11, wherein the controller isfurther configured to calculate a time at which a wheel of the vehicleassociated with the at least one adjustable damping device reaches arelative height point, wherein the calculated time depends on at leastone of a direction of travel of the vehicle and a speed of the vehicle,wherein the second control term at the time at which the wheel reachesthe relative height point is used by the controller to generate thecontrol signal to control the at least one damping device.
 13. Thesuspension system as claimed in claim 11, wherein the controller isfurther configured to calculate an absolute height profile of the groundsurface area from the optically recorded information.
 14. The suspensionsystem as claimed in claim 13, wherein the controller is furtherconfigured to reprocess the optically recorded information to obtain theabsolute height profile and compensate for inherent movements of atleast one of a structure of the vehicle and of movements of the vehicle.15. The suspension system as claimed in claim 9, wherein the controlleris further configured to reconstruct missing height points in theoptically recorded information between a detection region disposed infront of the vehicle for the optically recorded information and a wheelassociated with the at least one damping device.
 16. A vehiclecomprising a suspension system as claimed in claim
 9. 17. The method asclaimed in claim 1, wherein the adaptive suspension system is anadaptive air spring system.
 18. The suspension system as claimed inclaim 9, wherein the adaptive suspension system is an adaptive airspring system.
 19. A method of controlling a suspension system for avehicle, comprising: receiving, at a controller, a first input based oncurrent driving dynamics data and a second input based on opticallyrecorded information relating to a conditions of ground the vehicle willtravel on; generating a control signal based on at least one of firstand second inputs; and adjusting a damping characteristic of the atleast one damping device based on the control signal, wherein thesuspension system is an adaptive suspension system or an active rollcontrol suspension system.
 20. A suspension system, comprising: anoptical system configured to record ground conditions of ground thevehicle will travel on; an adjustable damping device, wherein thesuspension system is an adaptive suspension system or an active rollcontrol suspension system; and a controller configured to: receive afirst input based on current driving dynamics data and receive a secondinput based on information recorded by the optical system, and adjust atleast one characteristic of the damping device based on at least one ofthe first and second inputs.